CN105374958B

CN105374958B - Secondary battery

Info

Publication number: CN105374958B
Application number: CN201510494540.4A
Authority: CN
Inventors: 李钟夏; 龙俊善
Original assignee: Samsung SDI Co Ltd
Current assignee: Samsung SDI Co Ltd
Priority date: 2014-08-13
Filing date: 2015-08-12
Publication date: 2020-03-20
Anticipated expiration: 2035-08-12
Also published as: EP2985807A1; EP2985807B1; CN105374958A; KR102273786B1; US10044008B2; JP6769590B2; KR20160020060A; US20160049623A1; JP2016042464A

Abstract

According to an aspect of an embodiment of the present invention, a secondary battery includes: an electrode assembly including a first electrode plate, a second electrode plate, and a separator between the first electrode plate and the second electrode plate; a can including an opening formed at one end thereof to receive the electrode assembly; a cover plate configured to seal an opening of the can, the cover plate comprising: the optical element includes a first surface, a second surface parallel to the first surface, a third surface joining the first and second surfaces and having a constant height, and a slope at a portion of the first surface contacting the third surface, wherein the slope has a varying slope.

Description

Secondary battery

Cross Reference to Related Applications

This application claims priority and benefit to korean patent application No. 10-2014-0104861, filed on 8/13 of 2014 to the korean intellectual property office, the disclosure of which is incorporated herein by reference in its entirety.

Technical Field

One or more exemplary embodiments of the present invention relate to a secondary battery.

Background

Unlike a primary battery that cannot be recharged, a secondary battery can be repeatedly charged and discharged, and has been widely used in small advanced electronic devices such as mobile phones, Personal Digital Assistants (PDAs), and notebook computers.

As the secondary battery is more commonly used in various fields, it becomes important to secure the reliability of the secondary battery according to the environment in which the secondary battery is used. For example, in order to ensure the reliability of the secondary battery, the secondary battery may be sealed from the external environment. If the secondary battery is not completely sealed, problems such as leakage of an electrolyte may occur when the secondary battery is dropped or damaged due to strong external impacts. Therefore, the secondary battery may not operate normally.

Disclosure of Invention

One or more exemplary embodiments of the present invention include a secondary battery that may be relatively easily sealed from the outside or the outside environment.

Additional aspects will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the exemplary embodiments set forth.

According to an aspect of an embodiment of the present invention, a secondary battery includes: an electrode assembly, comprising: a first electrode plate, a second electrode plate and a separator between the first electrode plate and the second electrode plate; a can including an opening formed at one end thereof to receive the electrode assembly; and a cover plate configured to seal an opening of the can, the cover plate including a first surface, a second surface parallel to the first surface, a third surface coupling the first surface and the second surface and having a constant height, and a slope (chamfer) at a portion of the first surface contacting the third surface, wherein the slope has a varying slope.

The first surface of the cover plate may face the inside of the can, and the second surface of the cover plate may face the outside of the can.

The cover plate may extend in a length direction, and the slope may include: a first slope formed on a first edge in a length direction of the cap plate; and a second slope formed on a second edge of the cover plate in the width direction, wherein a slope of the first slope is greater than a slope of the second slope.

The slope of the first ramp may be variable and the slope of the second ramp may be constant.

The first edge of the cover plate may be curved, and among the edges of the first slope, a portion of the first edge closest to the outside of the cover plate may have a maximum slope.

The slope of the first slope may gradually increase from a portion coupled to the second slope to a portion of the first edge closest to an exterior of the cover plate.

The height of the first slope may be less than or equal to 70% of the height of the third surface of the cover plate.

The length of the first slope may be greater than the length of the second slope.

The first edge of the cover plate may be curved, and among the edges of the first slope, a portion of the first edge closest to the outside of the cover plate has a maximum length.

The length of the first slope may gradually increase from a portion coupled to the second slope to a portion of the first edge closest to an exterior of the cover plate.

According to an aspect of an embodiment of the present invention, a secondary battery includes: a can including an opening formed on one end thereof; an electrode assembly in the can, wherein the opening of the can is configured to receive the electrode assembly; and a cover plate having a constant thickness and configured to seal an opening of the can, wherein the cover plate includes a slope formed on an edge of the cover plate and located inside the can, wherein the slope has a slope increasing toward a portion of the rounded end of the cover plate closest to an outside of the cover plate.

Drawings

These and/or other aspects will become apparent and more readily appreciated from the following description of the exemplary embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic perspective view of a secondary battery according to an exemplary embodiment of the present invention;

fig. 2 is an exploded perspective view of the secondary battery of fig. 1;

FIG. 3 is a cross-sectional view taken along line III-III of FIG. 1;

FIG. 4 is a bottom view of area A of FIG. 3;

FIG. 5 is a schematic side view of FIG. 4; and

fig. 6 is a sectional view taken along line VI-VI of fig. 4.

Detailed Description

While the invention is susceptible to various modifications and alternative embodiments, specific exemplary embodiments have been shown in the drawings and will be described in greater detail in the written description. However, it is not intended to limit the present invention to the particular mode of practice, and it will be understood that all changes, equivalents, and substitutions that do not depart from the spirit and technical scope of the present invention are encompassed by the present invention. In the description of the present invention, some detailed explanations of related arts are omitted when it is considered that they may unnecessarily obscure the characteristics of the invention.

The present invention will hereinafter be described in detail by explaining exemplary embodiments of the invention with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements, and a repetitive description thereof will be omitted.

It will be understood that, although the terms "first," "second," etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Aspects of embodiments of the present invention will be described in detail hereinafter by explaining exemplary embodiments of the invention with reference to the accompanying drawings.

It will be further understood that the terms "comprises" and/or "comprising," when used herein, specify the presence of stated features or components, but do not preclude the presence or addition of one or more other features or components.

It will be understood that when a layer, region or component is referred to as being "formed on" another layer, region or component, it can be directly or indirectly formed on the other layer, region or component. That is, for example, intervening layers, regions, or components may be present.

In the following examples, the x-axis, y-axis, and z-axis are not limited to three axes of a rectangular coordinate system, and may be explained in a broader sense. For example, the x-axis, y-axis, and z-axis may be perpendicular to each other, or may represent different directions that are not perpendicular to each other.

The size of components in the drawings may be exaggerated for convenience of explanation. In other words, since the sizes and thicknesses of components in the drawings are arbitrarily illustrated in the drawings for convenience of explanation, the following exemplary embodiments are not limited thereto.

Fig. 1 is a schematic perspective view of a secondary battery 100 according to an exemplary embodiment of the present invention, and fig. 2 is an exploded perspective view of the secondary battery 100 of fig. 1. Fig. 3 is a sectional view taken along line III-III of fig. 1.

Referring to fig. 1 to 3, a secondary battery 100 may include an electrode assembly 110, a can (or case) 120 accommodating the electrode assembly 110, and a cap plate 130 sealing the inside of the can 120.

The electrode assembly 110 may include first and

second electrode plates

111 and 112 on which electrode active materials are respectively dispersed or deposited, and a separator 113 between the first and

second electrode plates

111 and 112. The electrode assembly 110 has a stacked structure in which a first electrode plate 111, a second electrode plate 112, and a separator 113 are sequentially stacked, and then may be wound to form a jelly-roll structure. The first and

second electrode plates

111 and 112 are electrically coupled to first and

second electrode tabs

114 and 115, respectively, for discharging charges generated due to a chemical reaction. The first and

second electrode tabs

114 and 115 may extend in the same direction. For example, the first and

second electrode tabs

114 and 115 may extend toward the opening OP of the can 120.

The first electrode plate 111 may include a first metal collector, and a first active material portion formed after a first active material is dispersed or deposited on the first metal collector. Similarly, the second electrode plate 112 may include a second metal collector, and a second active material portion formed after a second active material is dispersed or deposited on the second metal collector.

The first electrode plate 111 is formed of a positive electrode film, and the first metal collector is a positive electrode collector. The first active material portion may be a positive electrode active material portion. Further, the second electrode plate 112 is formed of a negative electrode film, and the second metal collector is a negative electrode collector. The second active material portion may be a negative active material portion. The materials and structures of the positive electrode collector, the positive electrode active material part, the negative electrode collector, and the negative electrode active material part may include well-known materials used in general primary batteries, and thus detailed descriptions about the materials and structures may be omitted.

The separator 113 may be a porous polymer film such as a polyethylene film or a polypropylene film, and may be formed of a nonwoven fabric or a woven fabric including polymer fibers. In addition, the separator 113 may include ceramic particles, and may be formed of a polymer solid electrolyte. The separator 113 may be formed as a separate film, or may be used after the non-conductive porous layer is formed on the first and

second electrode plates

111 and 112.

The separator 113 may be used to electrically separate the first electrode plate 111 and the second electrode plate 112, and the separator 113 may have a different shape from the first electrode plate 111 and the second electrode plate 112.

In the present exemplary embodiment, the electrode assembly 110 has a jelly roll shape, but the present invention is not limited thereto. As another exemplary embodiment, the electrode assembly 110 may have a stack structure in which a first electrode plate 111, a second electrode plate 112, and a separator 113 positioned therebetween are stacked.

The can 120 may be hexahedral shape and have an opening at one end, i.e., an end corresponding to the upper surface of the can 120. The can 120 may be formed of a metal material to obtain rigidity. For example, the can 120 may be formed of aluminum (Al) or an Al alloy. The electrode assembly 110 immersed in the electrolyte may be received within the can 120. In this case, the electrode assembly 110 may be accommodated within the can 120, surrounded by the insulating holder 170, to prevent an undesired short circuit (or reduce a short circuit condition) between the electrode assembly 110 and the can 120 formed of a metal material. After the electrode assembly 110 is received in the can 120, the opening OP may be sealed by the cap plate 130. A portion of the can 120 contacting the cap plate 130 may be coupled to the cap plate 130 by laser welding, and thus the inside of the can 120 may be airtight.

The cap plate 130 may include an electrolyte injection hole 131. After the cap plate 130 is coupled to the can 120, the electrolyte may be injected through the electrolyte injection hole 131, and the electrolyte injection hole 131 may be sealed by the cap 132. As another example, the cap plate 130 may not include the electrolyte injection hole 131. In this regard, the electrolyte may be injected before the can 120 and the cap plate 130 are coupled to each other by laser welding.

The electrode pin 140 may be located on the cap plate 130. The upper portion of the electrode pin 140 is exposed to the outside through the upper surface of the cap plate 130, and the lower portion of the electrode pin 140 may penetrate the cap plate 130 and may face the inside of the can 120.

The cover plate 130 may be positioned on the upper surface of the can 120 to seal the opening OP of the can 120. The cap plate 130 may be formed of the same metallic material, such as Al or Al alloy, used to form the can 120. As shown in fig. 3, the electrode pin 140 is electrically coupled to the first electrode tab 114 of the electrode assembly 110, and may have a first polarity. The cap plate 130 is electrically coupled to the second electrode tab 115 of the electrode assembly 110, and may have a second polarity. The can 120 coupled to the cap plate 130 by welding may also have the second polarity.

For example, the cap plate 130 may serve as a positive electrode of the secondary battery 100, and the electrode pin 140 may serve as a negative electrode thereof. In this case, a first pad 145 and a second pad 146 including suitable insulating (or insulating) materials to prevent a short circuit (or reduce a short circuit condition) between the cap plate 130 and the electrode pin 140 may be disposed between the cap plate 130 and the electrode pin 140. The first gasket 145 may be positioned to contact the upper surface of the cap plate 130, and the second gasket 146 may be positioned to contact the lower surface of the cap plate 130. In fig. 2, the first and

second spacers

145 and 146 are separated, but the first spacer 145 and the second spacer 146 may be formed as a single part. An insulating film 160 covering the side of the can 120 may be attached to electrically insulate the can 120 having the second polarity and coupled to the cap plate 130 by welding from an external product or another secondary battery.

The first insulating member 150 positioned on the upper surface of the electrode assembly 110 may be positioned within the can 120. The first insulating member 150 may insulate the electrode assembly 110 from the cap plate 130. As another example, the first insulating member 150 insulates the electrode assembly 110 from the cap plate 130, and may control the movement of the electrode assembly 110 in the can 120. The first insulating member 150 includes a through-hole through which the first and

second electrode tabs

114 and 115 may pass, and may include a hole formed at a position corresponding to the electrolyte injection hole 131 such that the electrolyte may be injected into the electrolyte injection hole 131. The second insulating member 180 is located on the lower surface of the electrode assembly 110, and may prevent an undesired short circuit (or reduce a short circuit condition) between the can 120 formed of a metal material and the electrode assembly 110.

Referring to fig. 3, the cap plate 130 may be positioned on the upper surface of the can 120 to seal the opening OP of the can 120, and may be formed of a metal material, such as Al or Al alloy, that is the same metal material used to form the can 120. The opening OP of the can 120 may be sealed by the cover plate 130 using various methods. In this specification, an interference fit design is described, but the invention is not limited thereto.

When the inner diameter of the can 120 has a size of a, the size of the cap plate 130 may be a + α. the opening OP of the can 120 may be sealed by inserting the cap plate 130 into the inside of the can 120. in this case, stress is applied to one end a of the cap plate 130 extending in the length direction (X-axis direction), and thus the cap plate 130 formed of a metal material may be bent or flexed, thereby causing the secondary battery 100 to malfunction.

As shown in fig. 3, the cap plate 130 extends in a length direction (X-axis direction), and may include a first surface 133, a second surface 135 parallel to the first surface 133, and a third surface coupling the first surface 133 and the second surface 135 and having a constant height T. That is, the cap plate 130 has a thickness corresponding to the height T of the third surface 137. In this case, the first surface 133 may be disposed to face the inside of the tank 120, and the second surface 135 may be disposed to face the outside of the tank 120. The slope 130c may be formed at a portion of the first surface 133 contacting the third surface 137. The slope of the ramp 130c may be variable. In one embodiment, the slope of the slope 130c may increase toward a portion of the rounded end of the cover plate 130 closest to the exterior of the cover plate 130.

Hereinafter, the slope 130c formed at the edge of the cap plate 130 will be described in more detail.

Fig. 4 is a bottom view of the area a of fig. 3, and fig. 5 is a schematic side view of fig. 4. Fig. 6 is a sectional view taken along line VI-VI of fig. 4.

Fig. 4-6 illustrate one end a of the cover plate 130, providing a detailed description of one end a. The description about the other end B of the cap plate 130, which is not shown in fig. 4 to 6, will be the same as the description about the one end a.

Referring to fig. 4 to 6, the cap plate 130 may include a first surface 133, a second surface 135 parallel to the first surface 133, and a third surface coupling the first and

second surfaces

133 and 135 and having a constant height T. Fig. 4 shows a first surface 133 of the cover plate 130, the first surface 133 facing the inside of the can 120. As described above, the slope 130c is formed at a portion of the first surface 133 contacting the third surface 137, and the slope of the slope 130c may be variable.

The cover plate 130 has a first edge 130e1 in the length direction (X-axis direction) and a second edge 130e2 in the width direction of the cover plate 130. The first slope 130c1 is located on the first edge 130e1 and the second slope 130c2 is located on the second edge 130e 2. In this case, the slope of the first slope 130c1 is different from the slope of the second slope 130c 2. That is, the slope of the first slope 130c1 is greater than the slope of the second slope 130c 2. In one embodiment, the first edge 130e1 may be curved.

The slope of the first slope 130c1 is variable, and of the edges of the first slope 130c1, the portion of the first edge 130e1 farthest toward the outside of the cover plate 130 has the greatest slope. That is, the slope gradually increases from the portion of the first slope 130c1 coupled to the second slope 130c2 to the portion of the first edge 130e1 farthest toward the outside of the cover plate 130. The maximum amount of stress occurs at the portion of the cap plate 130 farthest toward the outside of the cap plate 130. Accordingly, the slope is designed to be gradually increased, and a steeper taper is formed on a portion of the cap plate 130, thereby minimizing the amount of stress applied to the cap plate 130.

On the other hand, the slope of the second slope 130c2 is constant along the second edge 130e2 of the cover plate 130. Therefore, the height t2 and the width w2 of the second slope 130c2 are always the same.

Fig. 5 illustrates the slope of the first slope 130c1 at the portion of the first edge 130e1 of the cover plate 130 that is farthest outward of the cover plate 130. The slope of the first ramp 130c1 at the portion of the first edge 130e1 of the cover plate 130 furthest toward the exterior of the cover plate 130 is equal to the height t1 of the first ramp 130c1 divided by the width w1 of the first ramp 130c 1. The height t1 of the first ramp 130c1 is greater than the width w1 of the first ramp 130c 1. At the position where the slope of the first slope 130c1 is the greatest, the ratio of the width w1 of the first slope 130c1 and the height t1 of the first slope 130c1 may be 1: 2. if the width w1 of the first ramp 130c1 is about 0.2 millimeters, the height t1 of the first ramp 130c1 may be 0.4 millimeters.

Referring to fig. 6, the slope of the second slope 130c2 is equal to the height t2 of the second slope 130c2 divided by the width w2 of the second slope 130c 2. The height t2 of the second ramp 130c2 is substantially the same as the width w2 of the second ramp 130c 2. That is, the ratio of the height t2 of the second ramp 130c2 to the width w2 of the second ramp 130c2 is about 1: 1. if the width w2 of the second ramp 130c2 is about 0.2 millimeters, the height t2 of the second ramp 130c2 is about 0.2 millimeters. Accordingly, among the slopes of the portions of the first slope 130c1, the slope of the portion of the first slope 130c1 having the greatest slope may be two times greater than the slope of the second slope 130c 2.

The cover plate 130 has a first edge 130e1 in the length direction (X-axis direction) of the cover plate 130 and a second edge 130e2 in the width direction (Y-axis direction) of the cover plate 130. The first slope 130c1 is located on the first edge 130e1 and the second slope 130c2 is located on the second edge 130e 2. In this case, as shown in fig. 4, the width w1 of the first slope 130c1 in the X-axis direction is the same as the width w2 of the second slope 130c2 in the Y-axis direction. The width w1 of the first ramp 130c1 and the width w2 of the second ramp 130c2 may be about 0.2 millimeters.

The cap plate 130 has a thickness corresponding to the height T of the third surface 137, and as shown in fig. 5, the height T1 of the first slope 130c1 may be less than or equal to 70% of the height T of the cap plate 130 based on the portion of the first slope 130c1 having the greatest slope. If the height T1 of the first slope 130c1 is equal to or greater than 70% of the height T of the cap plate 130, the strength of the cap plate 130 supporting the inner wall of the can 120 is weakened, and defects may occur when the can 120 is coupled to the cap plate 130 by welding.

Referring to fig. 5 and 6, because the slope of the first slope 130c1 is different from the slope of the second slope 130c2, the length d1 of the first slope 130c1 may be different from the length d2 of the second slope 130c 2. The length d1 of the first ramp 130c1 may be greater than the length d2 of the second ramp 130c 2. The length of the first slope 130c1 may be greatest at a portion of the first edge 130e1 farthest toward the outside of the cap plate 130. The first slope 130c1 gradually increases in length from a portion of the first slope 130c1 coupled to the second slope 130c2 to a portion of the first edge 130e1 farthest toward the outside of the cover plate 130, and the length of the first slope 130c1 may be largest at a portion of the first edge 130e1 farthest toward the outside of the cover plate 130.

Because the steeper taper is formed at the portion of the cap plate 130 farthest toward the outside of the cap plate 130 and because the maximum amount of stress within the can 120 occurs at that portion of the cap plate 130, the gradual increase in length of the first chamfer 130c1 may minimize the amount of stress applied to the cap plate 130.

By the above-described design of the cap plate 130, the shape overlap between the can 120 and the cap plate 130 can be improved by minimizing the bending deformation of the cap plate 130 and forming a variable slope at a portion of the cap plate 130 without changing the material of the cap plate 130. As a result, a secondary battery having greatly improved characteristics or depth can be realized.

As described above, according to one or more of the above-described exemplary embodiments of the present invention, a secondary battery that can endure external impact and internal expansion can be realized. However, the scope of the present invention is not limited thereto. Features of the present invention can be derived from the description provided above with reference to the drawings.

It is to be understood that the example embodiments described herein are to be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each exemplary embodiment should generally be considered as available for other similar features or aspects in other exemplary embodiments.

Although one or more exemplary embodiments of the present invention have been described with reference to the accompanying drawings, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims and their equivalents.

Claims

1. A secondary battery comprising:

an electrode assembly, comprising:

a first electrode plate;

a second electrode plate; and

a separator between the first electrode plate and the second electrode plate;

a can including an opening formed at one end thereof to receive the electrode assembly; and

a cover plate configured to seal the opening of the can, the cover plate comprising:

a first surface;

a second surface parallel to the first surface;

a third surface coupling the first surface and the second surface and having a constant height; and

a bevel at a portion of the first surface contacting the third surface, wherein the bevel has a varying slope,

wherein the cover plate extends in the length direction, and

the inclined plane includes:

a first slope formed on a first edge of the cap plate in the length direction; and

a second slope formed on a second edge in the width direction of the cap plate,

wherein the slope of the first slope is greater than the slope of the second slope.

2. The secondary battery according to claim 1, wherein the first surface of the cap plate faces the inside of the can, and the second surface of the cap plate faces the outside of the can.

3. The secondary battery according to claim 1, wherein the slope of the first slope is variable, and the slope of the second slope is constant.

4. The secondary battery according to claim 3, wherein the first edge of the cap plate is curved, and of the edges of the first slope, a portion of the first edge closest to the outside of the cap plate has a maximum slope.

5. The secondary battery according to claim 4, wherein the slope of the first slope gradually increases from a portion coupled to the second slope to the portion of the first edge closest to an exterior of the cap plate.

6. The secondary battery according to claim 5, wherein a height of the first slope is less than or equal to 70% of a height of the third surface of the cap plate.

7. The secondary battery according to claim 1, wherein a length of the first slope is greater than a length of the second slope.

8. The secondary battery according to claim 7, wherein the first edge of the cap plate is curved, and of the edges of the first slope, a portion of the first edge closest to the outside of the cap plate has a maximum length.

9. The secondary battery according to claim 8, wherein the length of the first slope gradually increases from a portion coupled to the second slope to the portion of the first edge closest to an outside of the cap plate.

10. A secondary battery comprising:

a can including an opening formed on one end of the can;

an electrode assembly in the can, wherein the opening of the can is configured to receive the electrode assembly; and

a cover plate having a constant thickness and configured to seal the opening of the can, wherein the cover plate includes a slope formed on an edge of the cover plate and located inside the can,

wherein the slope has a slope that increases toward a portion of the rounded end of the cover plate that is closest to an exterior of the cover plate,

wherein the cover plate extends in the length direction, and

the inclined plane includes:

a second slope formed on a second edge in the width direction of the cap plate,